1. SPORT INJURIES AND BIOMECHANICS ACL RUPTURE

2. ANATOMY Intra capsular knee joint structure Length 38mm( 25 to 41mm) Width 10mm (7 to 12mm) Made up multiple collagen fibers Surrounded by synovial membrane envelope

6. ANATOMY Femoral proximal attachment :postero- lateral corner of inter condylar notch Tibial distal attachment : front and lateral of anterior tibial spine Two bands: small anteromedial and a larger posterolateral portion

8. BIOMECHANICS Posterolateral bulky portion is tight in extension Anteromedial bundle is tight in flexion Ultimate tensile load :2160 +/- 157 N Approx 85% resistance to anterior tibial displasment

9. Maximum laxity in 30 deg flexion

10. Biomechanical characteristics ACL does not remain an isometric or constant length structure Unsectioned ACL :2-5mm anterior translation at full extension 5-8 mm at 30 deg flexion by application 100N anterior force

12. ACL rupture Common and severe injury particularly in compact sports as rugby Usual mechanism of injury knee hyperextension or external rotation in flexion

19. AP instability 7-9 mm of increased translation (100N anterior force) Supporting structures in ACL rupture: iliotibial band 24% medial capsule 22% lateral capsule 20% MCL 16% LCL 12% Quadriceps and hamstrings in a certain degree also Baratta et al 1988

21. Moment vs. time. Examples of quadriceps avoidance Devita et all 1998 Timony et all 1993

23. Matt Gaudet 2000

24. Load deformation curve Deformation Load Elastic Region Plastic Region Yield Point Ultimate Failure Point

27. THANK YOU